Feeding an oil from Lunaria biennis rich in 22:1n-9 and 24:1n-9 to homozygous quaking (qk.qk) mice caused a large increase in the percentage of 24:1n-9 and corresponding decreases in the percentage of 24:0 and 22:0 in sphingomyelins from liver, erythrocytes, and milk. Brain sphingomyelin from 2-wk-old qk.qk pups born to qk.qk mothers maintained on the Lunaria oil had essentially normal percentage of 24:1n-9 and 18:0, in contrast to pups born to mothers maintained on a control oil rich in 18:1n-9 whose brain sphingomyelin had a markedly reduced percentage of 24:1n-9 and an increased percentage of 18:0. After 2 wk and up to and beyond weaning, the qk.qk pups from Lunaria-fed mothers weaned on to the Lunaria diet had a markedly decreased percentage of 24:1n-9 in their brain sphingomyelin, accompanied by an increased percentage of 18:0, as compared to heterozygous quaking mice. However, the percentage of 24:1n-9 in brain sphingomyelin in qk.qk pups weaned on to the Lunaria diet continued throughout this period (2-8 wk postbirth) to be significantly higher than in qk.qk pups weaned on to the control diet. We conclude that dietary 24:1n-9 influences the fatty acid composition of brain sphingomyelin in qk.qk mice, but only via the mother in pre- or early postnatal animals. We further consider that the dietary effects may be elicited mainly in the sphingomyelin of nonmyelinated brain cells, and that the nervonic acid in myelin sphingomyelin may be formed mainly by chain elongation in oligodendrocytes from shorter chain fatty acid precursors.

Cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.) are the major agronomic crops grown in the Texas Rolling Plains, and sorghum [Sorghum bicolor (L.) Moench.] is an adapted high residue crop that is grown on a limited scale. Much of the cotton is grown in continuous monoculture (CC), largely because it is considered to be the most profitable crop for the area. Also, acreage bases restrict individual farms to a monoculture operation. High residue crops now are required in Conservation Compliance Plans. The primary objective of the present study was to determine the effects of combinations of cropping and tillage systems on cotton production. A study comparing the effects of tillage and crop rotations on cotton production was conducted for 8 yr (1985–1992) in the Texas Rolling Plains. Reduced (RT) and conventional (CT) tillage systems were used in combination with a wheat‐cotton rotation in a fallow system (WFC). Cotton was grown in rotation with sorghum (SC) in the RT system. Furrow diking was used in RT systems. Continuous cotton in the RT system produced yields equal to those from the SC rotation, and significantly greater than those from CC‐CT. Cotton in the WFC systems produced yields equivalent to those in the CC‐RT system. The CC‐RT system is a viable system on land not susceptible to erosion. The SC‐RT system provided the best alternative for highly erodible land because a crop is obtained each year. The WFC systems produce only two crops in 3 yr. Research Question Much of the cotton produced in the Texas Rolling Plains is grown in continuous, monoculture (CC) with conventional tillage (CT) systems that use multiple land preparation operations including chiseling, sweep‐plowing, and disking operations. Cotton can be rotated with grain crops that return more residue to the soil. Do rotational systems that return residue to the soil result in equal or higher cotton production? Do reduced tillage (RT) practices in combination with rotational systems that leave more surface residue conserve water and increase cotton production? Literature Summary Reduced tillage systems with furrow diking have been shown to increase yields and profitability of continuous, monoculture cotton in the semiarid Texas Rolling Plains. Rotational systems in many areas are reported to increase surface residue, reduce runoff, increase soil water accumulation, and increase yields of following crops. Rotational systems have received little attention in the Rolling Plains, and the combined effects of rotational systems with reduced tillage and furrow diking have not been reported for the area. This study was designed to determine the effects of reduced tillage and rotational systems of sorghum and wheat on cotton. Study Description The study was located at the Texas Agricultural Experiment Station in Chillicothe, Hardeman County (34.1° N lat, 99.3° W long, elev. 1406 ft). Mean annual precipitation is 24.87 in. (88‐yr mean). Soil type at the test site is an Abilene clay loam with a cross‐ and downslope of approximately 0.2%. Ini...

THE investigation of the lupin [McKie, 1931], an asparagine-producing plant, has been followed by that of the pea, in which no asparagine or other amide is formed in any amount, with a view to elucidating still further the part played by the various nitrogen metabolites. Similar conditions have been observed, and at the same time a parallel investigation of certain aspects of etiolated pea seedlings has been made. EXPERIMENTAL. Pea seeds (Pisum sativum), about 6-12 per pot, were grown in batches of 50 in a good potting mixture from January to April, 1935. The temperature of the greenhouse varied from 50 to 670 F. For no batch were conditions extreme or in any way adverse. The harvesting and preparation of material for analysis were carried out as for the lupin [McKie, 1931]. Drying. The temperature recommended by Link and Schulz [1924] was finally adopted. The seedlings, from spirit, were dried at 650 for 3 hours, then ground to a fine powder in a mill and the meal thinly spread on filter-paper and dried in an air incubator at 650 for 48 hours. Analyses for total N (Kjeldahl), were made on this dried material. Extraction ofmaterial. The dried and weighed material (6-7 g.) was intimately ground for 20 min. with 50 ml. of ammonia-free water and filtered through fine (mesh 0-017 cm.) weighed and dried muslin. This process was repeated, 6 times in all, using 30 ml. of water for each subsequent extraction, each muslin being pressed as dry as possible. The residue was dried to constant weight at 1050. Analyses were carried out as follows: Residue. Total-N was estimated by Kjeldahl and expressed as "Insoluble N". Filtrate. The combined washings were made up to 500 ml. (250 ml. for 0 (a) and 3 (a and b) days and 1000 ml. for 32 days); with ammonia-free water and analysed for total N and individual water-soluble N compounds. Analyses for total N, proteose, ammonia, amide and nitrate were performed as described for the lupin. Protein. Owing to the presence in the pea of legumin, a protein soluble in acidulated water and incompletely coagulated by heat, a modified method of precipitation and filtration based on a study of the optimum conditions was adopted. The PH of the extract was adjusted to 4 5, the isoelectric point of legumin, by addition of acetic acid, and the extract gently boiled for 1 hour. The coagulum was filtered hot through hardened filter-paper (Whatman No. 50) under slight pressure, repeatedly washed with hot water and dried to constant weight at 1050. Analyses for total N were then made on this material. Proteose. Since some legumin inevitably remains after coagulation, and since this residuum is precipitated byNa2SO4, the estimation of proteose by the method of Wasteneys and Borsook [1917] gives proteose plus this residual protein. 5 ml. of extract were used for each determination.